The present invention relates to a display screen switch, and more particularly to a display screen switch to be operated on a display screen on which switch information is displayed.
In recent years, in order to make a switch function a multi-purpose type, there was proposed a display screen switch to be operated on a display screen on which switch information is displayed.
As a display screen switch, there are some types of switches, such as a touch panel type which pushes down a touch panel itself on the display screen and another type which pushes down a transmit operational member on the display screen to make a contact type switch operate, or the like. The touch panel type lacks an input sense, as there is little operational stroke based on the push-down operation, but the type using the transmit operational m and a contact type switch does not lead to such disadvantage, as an operational stroke due to the push-down motion is enough.
The present inventors previously investigated and proposed a structure in which a display screen switch using the transmit operational member and a contact type switch was used (Japanese Patent Application No. 11-149295: not prior art).
In FIGS. 8 to 11, a display screen switch 1 includes a plate-like case 3 arranged on a display screen 2a of a liquid crystal display 2, a plurality of switch bodies 4 fixed to the case 3, a transmit operational plate 5 as a plurality of clear keys arranged on the outside of the case 3, a rubber 6 as a sheet-like elastic member intervened between a plurality of transmit operational plates 5 and the case 3, and a cover 7 for supporting each transmit operational plate 5.
The case 3 is made of ABS resin or polycarbonate resin, and includes a plate-like case body 3a arranged on a display screen 2a, and a plurality of juxtaposed transmit-illuminate windows 3b which are formed on the case body 3a so as to penetrate the case body 3a between the topside and the underside and through which switch information displayed on the display screen 2a is transmitted and illuminated to the transmit operational plate 5 side.
A plurality of switch bodies 4 are fixed to the respective positions of the case body 3a corresponding to a plurality of juxtaposed transmit-illuminate windows 3b and each switch body 4 has a contact using a metal contact.
Each transmit operational plate 5 includes a transparent display part 10 in which switch information is passed through transparently and displayed, a switch push-down part 11 provided on one side of the transparent display part 10, a flange 12 provided over all the outside circumference of both transmit display part 10 and switch push-down part 11, and an engagement wall part 13 provided extendedly at the down side of the flange 12. Each transmit operational plate 5 is made of, for example, methacryl (acryl resin) or polycarbonate resin.
In the transparent display part 10, a part which is required to transmit a light and a part which is not required to transmit a light are formed by a so-called two-color molding method of a transparent element and an opaque element. Further, in FIG. 10 and FIG. 11, a part which transmits a light is illustrated by a broken line hatching, while a part which prevents outer light leakage is shown by an ordinary resin-hatching. A top face 10a of the transparent display part 10 is a key top.
A rubber 6 is made of, for example, silicone gun and on the top face of the rubber 6, a plurality of holes 6a are arranged. An engagement wall 13 of each transmit operational plate 5 is inserted into each hole 6a, respectively and the rubber 6 is engaged with each transit operational plate 5 to exhibit its elasticity.
A cover 7 is made of ABS resin or polycarbonate resin and includes a plate-like cover body part 7a and a plurality of juxtaposed operational plate holes 7b which are formed on the cover body 7a so as to penetrate from both sides. The upper parts of the transparent display part 10 and the switch push-down part 11 of the transmit operational plate 5 are protruding from the operational plate hole 7b. The flange 12 of the transmit operational plate 5 is stuck to the case 3 by an elastic force of the rubber 6. That is to say, a distance between an upper face of the case 3 and a lower face of the cover 7 is set in response to a dimension a little less than a distance between a lower face of the rubber 6 in a free condition (in no load state) and an upper face of the flange 12 of transmit operational plate 5, and thus the transmit operational plate 5 is mounted downward in a little displaced way against an elastic force of the rubber 6. In FIG. 10 and FIG. 11, reference numeral 14 is a face part.
In the above constitution, a many sorts of information is selectively displayed on the display screen 2a of the Liquid crystal display 2, and switch information is displayed in a specified part of the display screen 2a corresponding to a plurality of transmit operational plate 5. A plurality of switch information shown on the display screen 2a is transparently displayed on the surface of the transparent display part 10 in every transmit operational plate 5. An operator looks at it and pushes a switch push-down part 11 of a desired transmit operational plate 5. Then, the switch push-down part 11 displaces downward by an elastic deformation of the rubber 6, and the switch push-down part 11 correspondingly pushes down the switch body 4 to activate the switch body 4.
In the course of the operation, the plate-like case 3 and the thin transmit operational plate 5 are arranged in a multilayer state on the display screen 2a of the liquid crystal display 2 to activate the switch body 4 fixed to the case 3 by the push-down operation of the transmit operational plate 5. Therefore, since a distance between the display screen 2a and an upper surface 10a of the transparent display part 10 in the transmit operational plate 5 which corresponds to a key top is short, an operator can easily observe switch information shown on the display screen 2a. 
If the switch push-down part 11 of the transmit operational plate 5 is pushed down, the rubber 6 is downward elastically deformed to activate the switch body 4, while if the push operation of the switch push-part 11 is stopped, the rubber 6 returns to the original position due to elastic return/deformation. And the rubber 6 is arranged under the all circumference of the transmit operational plate 5 and the rubber 6 is stuck to the transmit operational plate 5 due to its elastic reaction. Therefore, it is possible to prevent dust, water, or the like which entered into an operational hole part 7b of the cover 7 from entering inside.
Nevertheless, in the display screen switch 1 as investigated above, as the transmit operational plate 5 and the rubber 6 are only stuck thereto by an elastic reaction of the rubber 6 or the like, it may be supposed that after assembled, the transmit operational plate 5 produces a positional slide due to vibration or the like.
To solve the above problems, the present invention has been proposed and it is an object of the present invention to provide a display screen switch in which a transmit operational plate does not produce a positional slide after built-in and a good assembly accuracy can be obtained.
Specifically, a display screen switch of the present invention comprising: a plate-like case arranged on a display screen and provided with a transmit-light window part in which switch information displayed on the display screen is transmitted; a switch body fixed to the case; a cover arranged on an upper side of the case and having a hole part; a transmit operational member including a transparent display part which transmits a visible light and on which the switch information is displayed, and a switch push-down part which makes the switch body operate; and an elastic member interposed between the transmit operational member and the case along a circumference part of the transmit operational member. The transmit operational member is structred such that the transparent display part and the switch push-down part are arranged in a protruding way from the hole part, between the cover and the case. Especially, the elastic member and the transmit operational member are bonded by an adhesive.